It's technically possible for Valve to pull access to your entire library and games that use Steamworks DRM will no longer work in that circumstance, but as far

It's technically possible for Valve to pull access to your entire library and games that use Steamworks DRM will no longer work in that circumstance, but as far as I know it's very rare for them to do it at this point. They used to do it if you issued a chargeback, but they had to stop doing that since it was in violation of various government and payment processor policies.